1. Field of the Invention
The present invention relates to a cassette housing case for housing a magnetic tape cassette (also called a magnetic tape cartridge) in which a single reel with magnetic tape wound thereon is rotatably housed within a cassette case with similar longitudinal and transverse dimensions.
2. Description of the Related Art
A magnetic tape cassette in which a single reel with magnetic tape wound thereon is rotatably housed in a flat cassette case having a generally square flat form, and a magnetic disk cassette in which a disk is rotatably housed in a flat cassette case having a generally square flat form, have recently been used as storage media to back up data stored on memory for computers.
These cassettes are usually housed in their dedicated cassette housing cases when not being used, such as when being conveyed, when being archived, etc. In addition, the cassette is provided with a recording member, such as a bar code, a memory chip, etc., for identifying the recorded contents. It is important to provide a transparent portion (label area) in the cassette housing case and house the cassette in the cassette housing case in a fixed direction so that the recording member, such as a bar code, etc., can be read even in the housed state.
Furthermore, in order to enable transfer, transportation, and conveyance with a plurality of cassette housing cases stacked atop each other, the cassette housing cases are generally provided with a structure for regulating positional shift between the cassette housing cases when stacked. For instance, each cassette housing case is provided on the bottom surface with a protrusion and on the top surface with a recess. When a plurality of said housings are stacked together, the protrusion is fitted into the recess to regulate positional shift therebetween.
However, the engagement recess and protrusion in the top and bottom surfaces of the conventional cassette housing case are usually formed so that the lateral dimension and the vertical dimension differ from each other. When an upper cassette housing case is horizontally rotated through 90xc2x0 from a correct engagement position with respect to a lower cassette housing case, they cannot engage each other. However, when an upper cassette housing case is horizontally rotated through 180xc2x0 from a correct engagement position with respect to a lower cassette housing case, in many cases they engage each other. Because of this, there is a problem that the label areas of a plurality of cassette housing cases stacked together will not always be facing the same direction.
In addition, most of the cassettes are similar in longitudinal and transverse dimensions, and it is troublesome to identify the longitudinal and transverse lengths of a cassette and house the cassette into a housing case in a fixed direction. Because of this, there is another problem that housing of a cassette in an incorrect direction will disable reading of the aforementioned recording member at the label area.
The present invention has been made in view of the problems found in the prior art. Accordingly, it is a first object of the present invention to provide a cassette housing case which comprises an engagement recess and an engagement protrusion having patterns so that when a plurality of cassette housing cases are stacked together, the label areas of the cassette housing cases and the recording members of the cassettes are disposed in the same direction. A second object of the present invention is to provide a cassette housing case that is capable of preventing a cassette from being housed in an incorrect direction.
To achieve the first object of the present invention mentioned above, there is provided a first cassette housing case for regulating positional shift, comprising an engagement recess and an engagement protrusion. The engagement recess is formed in one of the top and bottom surfaces of the cassette housing case. The engagement recess has a pattern which is asymmetrical with respect to at least either a first center line drawn in the one surface in parallel with a reference surface, or a second line drawn on the one surface which bisects the first center line in a direction perpendicular to the first center line. The engagement protrusion is formed in the other of the top and bottom surfaces and has a corresponding pattern engageable with the engagement recess.
The reference surface used herein means, for example, a surface provided with a label area.
To achieve the second object of the present invention mentioned above, there is provided a second cassette housing case for regulating positional shift, comprising:
an engagement recess formed in one of top and bottom surfaces of the cassette housing case and having a pattern which is asymmetrical with respect to at least either a first center line drawn in the one surface in parallel with a reference surface, or a second line drawn on the one surface which bisects the first center line in a direction perpendicular to the first center line;
an engagement protrusion formed in the other of the top and bottom surfaces and having a corresponding pattern engageable with the engagement recess; and
a mark, provided on the top surface of the housing case, for indicating a direction in which a cassette is housed within the cassette housing case.
In the second cassette housing case, the indicating mark can be formed as a substantially triangular mark etched in the top surface of the housing case. The patterns of the engagement recess and protrusion can be also formed as substantially triangular shapes. In addition, it is preferable that the cassette housing case employ transparent or semitransparent material.
According to the first cassette housing case of the present invention, the engagement recess in one of the top and bottom surfaces of the cassette housing case has a pattern which is asymmetrical with respect to at least either a first center line drawn in the one surface in parallel with a reference surface, or a second line drawn on the one surface which bisects the first center line in a direction perpendicular to the first center line. The engagement protrusion in the other of the top and bottom surfaces has a corresponding pattern engageable with the engagement recess. With these patterns, the engagement between the recess and the protrusion becomes possible only in a correction direction, so a plurality of cassette housing cases can be stacked with the respective label areas disposed in the same direction.
According to the second cassette housing case of the present invention, the top surface of the cassette housing case is provided with a mark indicating a direction in which the magnetic tape cassette is housed. This makes it possible to prevent a cassette from being housing in an incorrect direction. In addition, in the case where the cassette housing case has no label area, the same advantage can be obtained by employing a cassette housing case formed from transparent or semitransparent material.